Merge bitcoin/bitcoin#31450: guix: disable gcov in base-linux-gcc

f6496a8388 guix: disable gcov in base-linux-gcc (fanquake)

Pull request description:

  In a `x86_64-linux-gnu` build, this drops:
  ```bash
  x86_64-linux-gnu/bin/x86_64-linux-gnu-gcov
  x86_64-linux-gnu/bin/x86_64-linux-gnu-gcov-dump
  x86_64-linux-gnu/bin/x86_64-linux-gnu-gcov-tool
  x86_64-linux-gnu/lib/gcc/x86_64-linux-gnu/12.4.0: libgcov.a
  ```

  For mingw-w64-gcc, `--disable-gcov` is currently passed for this target in Guix, due to issues with mingw-w64, see
  8bed031e58/gnu/packages/gcc.scm (L99-L102). However we'll add it in any case, in case it's re-enabled in future, when the underlying issues are fixed.

ACKs for top commit:
  TheCharlatan:
    ACK f6496a8388

Tree-SHA512: ad6de53f63e7bb658cac05fb023fb1f8e76103073c7dffb4267412d3046148e1389df8848010128c1bd3d428f05e1587b656ef2cad8c7d9078ebec83a68bad49

contrib/guix/manifest.scm

@@ -420,6 +420,7 @@ inspecting signatures in Mach-O binaries.")
             ;; https://gcc.gnu.org/install/configure.html
             (list "--enable-threads=posix",
                   "--enable-default-ssp=yes",
+                  "--disable-gcov",
                   building-on)))))))
 
 (define-public linux-base-gcc
@@ -435,6 +436,7 @@ inspecting signatures in Mach-O binaries.")
                   "--enable-default-pie=yes",
                   "--enable-standard-branch-protection=yes",
                   "--enable-cet=yes",
+                  "--disable-gcov",
                   building-on)))
         ((#:phases phases)
           `(modify-phases ,phases